daymark
n. a mark to help navigators to find their way

nimbiferous
adj. bringing storms or showers

kenspeckle
adj. easily recognizable, conspicuous

onymous
adj. having a name

During World War II, pilots in northern Australia noted that an enormous thunderstorm formed daily between September and March on the Tiwi Islands in the Northern Territory. Regularly reaching heights of 20 kilometers, “Hector the Convector” is one of the world’s largest thunderstorms, an object of concentrated study by meteorologists, and a relative oddity — a cloud with a name.